The rotating of ultrasound transducer arrays contained in ultrasound imaging apparatus in order to produce three-dimensional images is common in the prior art. For example, U.S. Pat. No. 5,662,116 issued to Kondo et al. discloses a multi-plane electronic scan ultrasound probe having a rotary member mounted on the distal end of an elongated catheter and an ultrasound transducer, namely a large number of ultrasound elements positioned in a row, mounted on the rotary member. The ultrasound probe has a tilting mechanism to tilt the rotary member which in turn tilts the ultrasound transducer.
Another patent, U.S. Pat. No. 5,159,931 issued to Pinni describes an apparatus which achieves the three-dimensional reconstruction of anatomic structures by acquiring two dimensional echographic images produced by real time processing of signals that are reflected and/or scattered by the structures when they are hit by an ultrasound beam generated by a piezoelectric transducer contained within an echographic probe. In use, the sector scan transducer rotates through a 180 degree angle around the longitudinal axis of the probe.
Another example of a rotating ultrasound transducer array used in an ultrasound imaging apparatus to create a three-dimensional image can be seen in U.S. Pat. No. 5,070,879 issued to Herres. The Herres patent discloses an ultrasound imaging apparatus having a probe disposed on a longitudinal axis and ultrasound transducer elements arranged along the axis of the probe. The ultrasound array alternates between remaining stationary and oscillating about the axis of the probe in order to define a sector. In the first mode, where the array is held stationary, the transducer elements are operated successively to generate a longitudinal rectilinear scan. In the second mode, where the array is oscillated, the transducer elements are repeatedly operated to generate a transverse sector scan orthogonal to the longitudinal scan. The transducer elements are operated in one mode repeatedly at all of the transducer element positions of the other mode to generate a three-dimensional scan.
Although the generation of the three-dimensional images using ultrasound imaging apparatus which contain ultrasound arrays that are rotated about a center axis is common in the field of art, there is a need for an improved ultrasound imaging apparatus for three dimensional ultrasound imaging which utilizes an ultrasound imaging apparatus that utilizes an array which can focus in the elevation dimension and that comprises a structural make-up which limits maintenance and failure of the apparatus